title: Differences in circumferential resection margin involvement after abdominoperineal excision and low anterior resection no longer significant.
abstract: OBJECTIVE
  The aim of this study was to evaluate whether the abdominoperineal excision (APE) is associated with an increased risk of circumferential resection margin (CRM) involvement after rectal cancer surgery in comparison with low anterior resection (LAR).
  
  
  BACKGROUND
  The oncologic inferiority of the APE technique in comparison with LAR has been widely reported in literature. However, because of large evolvement in rectal cancer care, outcomes after APE may have improved since then.
  
  
  METHODS
  The population-based dataset of the Dutch Surgical Colorectal Audit was used selecting 5017 patients with primary rectal cancer undergoing surgery in 2010 to 2011. Propensity scores were calculated for the likelihood of performing an APE given relevant patient and tumor characteristics, and used in the multivariate analysis of CRM involvement.
  
  
  RESULTS
  The APE was associated with a slight, nonsignificant, increased risk of CRM involvement [odds ratio (OR) = 1.33; confidence interval (CI) = 0.93-1.90]. Absolute percentages of CRM involvement were 8% and 12% after LAR and APE, respectively.In the subgroup analysis, advanced rectal tumors (cT3-4) were associated to a higher risk of CRM involvement after APE (OR = 1.61; CI = 1.05-1.90), whereas smaller tumors (cT1-2) were not (OR = 0.62; CI = 0.27-1.40).
  
  
  CONCLUSIONS
  The results suggest that on a national level the APE procedure itself is not a strong predictor anymore for CRM involvement after rectal cancer surgery. However, in advanced tumors, results after APE are inferior to LAR.
authors.affiliation: *Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands †Department of Surgery, Catharina Hospital, Eindhoven, The Netherlands ‡Departments of Clinical Epidemiology and Medical Statistics and Bioinformatics, Leiden University Medical Centre, Leiden, The Netherlands §Department of Surgery, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands ¶Department of Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Nicoline
authors.initials: N
authors.lastname: van Leersum
authors.forename: Ingrid
authors.initials: I
authors.lastname: Martijnse
authors.forename: Marcel
authors.initials: M
authors.lastname: den Dulk
authors.forename: Nikki
authors.initials: N
authors.lastname: Kolfschoten
authors.forename: Saskia
authors.initials: S
authors.lastname: Le Cessie
authors.forename: Cornelius
authors.initials: C
authors.lastname: van de Velde
authors.forename: Rob
authors.initials: R
authors.lastname: Tollenaar
authors.forename: Michel
authors.initials: M
authors.lastname: Wouters
authors.forename: Harm J
authors.initials: HJ
authors.lastname: Rutten
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010502:Perineum / Q000601:surgery*; D057216:Propensity Score; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000601:surgery*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult